The invention pertains to a process for the separation of solid matter from undistillable liquid hydrocarbon fractions, which, along with other product components, are produced in the refining of coal at high temperatures.
In the refining of coal, for example, its carbonization or liquefaction thru extraction or hydration, various gaseous and liquid hydrocarbons are produced as reaction products. These, insofar as they are distillable, can be separated in one or more distillation steps. As a rule, a hydrocarbon fraction is produced as a distillation residue thereby. This is enriched with the solid particles still contained in the reaction products, such as unchanged coal particles, ash particles, and, in the case of coal liquefaction, necessarily also catalyst particles.
In the case of coal liquifaction, the residue fraction consists essentially of bitumen, while in the case of bituminous coal carbonization, bituminous coal tar asphalt is produced, along with other products, as distillation residue.
In the refined state bituminous coal tar asphalt in particular is suitable as a raw material for the production of a valuable metallurgical coke which is needed in considerable quantities for electrometallurgical purposes.
The separation of solid particles from the liquid hydrocarbon fraction nevertheless caused great difficulties.
Known methods, such as filtration, sedimentation under the force of gravity, or also centrifuging, have not led, it appears, to the desired result.
The mixing of the solid-containing, liquid bitumen fraction produced as an end product of hydration with an aromatic bond containing benzene fraction is already known in the area of coal hydration. Through the mixing of the benzene fraction, it has indeed been possible to improve the filtering capacity of the bitumen, but the efficiency of the solid separation is nonetheless still not satisfactory.